No discussion of marriage is complete without some mention of the antithesis of marriage: adultery.

Go into any book store and you'll be greeted by rows and rows of books on the subject, written by people who hope to appear on the Oprah Winfrey show someday and tell us all what a deep and profound subject it is, and how worthy it is of all that space in the bookstore.

I don't believe that the subject of adultery deserves all this introspection and endless analysis. It is not nearly as complicated as people make it out to be, and I suspect the only reason they make such a fuss about it is to excuse it in some way, to grant it a mysterious and esoteric quality that it doesn't possess. Despite what Oprah Winfrey and others would like you to believe, there's only three things anyone needs to know about adultery, and they're pretty simple at that.

First,

Never be "faithful" to someone you're married to

I have never liked the word "faithful". Along with its close affiliates "fidelity" and "loyalty", it reinforces the idea that , for the married, temptation lurks around every corner and that only the most stalwart, the most "faithful" are strong enough to overcome the tidal wave of seduction and allure that plague the married heart. Many spouses take pride in how "faithful" they've been, as if they expect to be rewarded for having the moral fortitude to resist temptation and make the sacrifice of "only" sleeping with their spouse. "Loyalty" is praised highly in a spouse, as it is in a puppy who keeps coming back to lick your hand no matter how many times it's been kicked.

The word "faithful" should never be applied to a marriage partner. Why would you have to be faithful to something you love? How difficult is it to remain "loyal" to something that inspires you, delights you, fulfills and impresses you? It's not hard at all. It is far preferable to have a husband or wife who comes home to you each night because they don't want to be anywhere else, rather than one who trudges home because they are a good and faithful spouse.

If it is difficult for you, and you find it impossible to stay out of other people's beds while still sleeping in your spouse's each night, don't disguise your behavior with euphemistic expressions. The only proper term for a sexual or romantic relationship you have with someone outside your marriage is adultery. It is usually called anything but - from the childish and therefore less serious "cheating" (like you got caught looking over your classmate's algebra answers) to "an affair" which imbues it with an elegant air of class and discretion that most paltry little adulterous acts don't have. We also call it philandering - close enough to "philanthropy" that it somehow makes the philanderer seem like a pillar of the community, spreading his love around. Dalliances, indiscretions, flings; there's no end to the harmless little words we'll devise to excuse deception and dishonesty. It's adultery. And it doesn't have to be full blown sexual intercourse to qualify as adultery, either, despite what many of us would like to believe. In reality:

Anything you do that violates your spouse's sexual or romantic primacy is adultery

The question of what actually constitutes adultery has plagued the guilty consciences of millions of adulterous spouses over the years. The answer, which seems to change depending on who the current president is, has appeased those consciences as well. No one seems sure about what constitutes adultery, and in the absence of some sort of final judge, many people decide that what they're doing isn't really adultery, so they're not really doing anything wrong.

This perhaps, will be President Bill Clinton's lasting legacy. He effectively redefined sexual relations for the entire world, or tried to. Because of him, I'm sure millions of people are out getting blow jobs and going back to their wives with an unblemished soul because, hey, if the President of the United States says it isn't sex, who's to argue with that?

I am.

I don't think it takes a rocket scientist to figure out that oral sex with someone other than your spouse is, in fact, a violation of your wedding vows. But for those people who try to ignore reality and pretend that anything up to full penetration is okay, there is one simple question that should bring them back down to earth. If you want to know whether what you're doing is adulterous or not, ask yourself this: How would my spouse react if he or she knew what I was doing?

Would your wife pat your head and bring you a mug of cocoa if she found you engaging in chat room cyber-sex late at night? Would your husband shrug it off if he knew that you and the new guy at the office made out like teenagers at the Christmas party? What if your wife knew that you were carrying on an intimate, emotional relationship with another woman, flirting with her and telling her private details that no mere friend ought to know? Would she be comforted by the fact that you didn't actually have sex with the woman?

Of course not. You don't have to engage in intercourse or oral sex to have violated your spouse's primacy. And that's the key to adultery. As much as we might like to believe that a grope session on a stranger's couch or touchless internet sex has no bearing on marriage, the inescapable truth is that these things chip away at the primacy of marriage. I wrote about in an earlier page, and stressed how important it is for husbands and wives to be the primary - the only current - source of sexual and romantic love in their spouse's lives. No marriage can or should survive in the absence of this understanding. This is also true for those misguided couples who happily share each other with other swingers or look the other way when their spouse takes lovers; they don't have marriages in the true sense of the word, they have arrangements of convenience which aren't likely to last anyway. Whenever you violate your spouse's primacy by engaging in sexual or romantic activities with someone else, you are violating the very nature of marriage itself, which means:

Adultery signals the end of your marriage

If you or your spouse has committed adultery, there is no longer any basis for your marriage.

It's simple, really. Marriage is based on mutual love, admiration and respect. It celebrates the fact that you have found the most amazing person in the world, the person who delights you most. Happily married people are monogamous because they are with the only person they want to have sex with. It's only when you aren't in love with your spouse that adultery becomes a real possibility.

If it does occur, it's important to understand that the love that once defined your marriage has either disappeared or changed into some other kind of affection. It does not mean that there was just some little problem in your marriage that needed to be worked out, or that you were bored; many couples manage to overcome their problems or their boredom without committing adultery. Adultery is the final step in the dance. It is a clear indication that whatever else there may be between you - homes, children, well-established lives - there is simply no more love, and as such, the marriage should be dissolved.

There are many people who claim that they still love their spouse, even while they are warming the bed of another, and many more who decide to be moral and forgive the adultery. Some people even make the absurd claim that adultery saved their marriage. Countless people take their spouses back, giddy with assurances that things will be different from now on. The sad truth is that things will be different. Things will never be the same again.

No matter how people try to deny it, there's no way you'll ever forget that your husband or wife was intimate with someone else. That first time you get back into bed with each other, how easy will it be to erase the image of your husband or wife making love to someone else? Once your primacy has been violated, once your spouse allows another person to infiltrate the bond you two had forged in marriage, can you ever feel entirely intimate, entirely sexual, entirely married ever again?

No. The marriage, as it was, is over. The best you can do is part, amicably, and seek out someone who desires only you.

There are many people - mostly the people who write all those books - who believe that adultery is a lot more complicated than this, or that each situation is different. These are the people who are more interested in maintaining the accoutrements of marriage, the trappings and the external appearance of marriage, than in understanding the essence of it, and how it works.

Don't listen to them. They know as well as I do that adultery is the opposite of marriage, the death of it, and caused by only one thing: the irretrievable loss of love.